Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Skip the balancing act.
Here is how I do this:
1) Research the fish needs, especially the GH.
2) Test the tap water, or whatever source you are using for the aquarium. GH, KH, pH, TDS (if you have a meter).
3) Goal: set GH and KH pretty close to each other and ignore the pH.
3a) If the tap water has lower mineral levels than the fish you want:
Add Seachem Equilibrium to raise the GH to the right level.
Add baking soda or potassium bicarbonate to raise the KH to match the GH.
Ignore the pH. When the minerals are right, the fish are highly likely going to be fine at a very wide range of pH.
3b) If the tap water has higher GH or KH than the fish want, then blend reverse osmosis or distilled water with the tap water until the one that is too high is what the fish want. If this lowers the other one too much then correct as in part 3a). Ignore the pH.
3c) If you want to keep a soft water species that comes from a black water river or stream then it is a 2-part solution:
Get the GH and KH where the fish want (almost always this is very soft water- mostly reverse osmosis with just a little bit of tap water unless your tap water is very soft)
Circulate this water through peat moss to add the organic acids these fish are accustomed to.